KR101242750B1 - Manufacturing method of solid asphalt and manufacturing method of asphalt concrete using the same - Google Patents

Abstract

PURPOSE: A manufacturing method for solid asphalt is provided to facilitate a transportable mixing plant, and to simplify plant facilities by excluding asphalt kettles and a delivering apparatus. CONSTITUTION: A manufacturing method for non-modified solid asphalt comprises the following steps of: (a) manufacturing non-modified asphalt by adding a binder additive to asphalt; (b) preparing a solidifier by mixing calcium carbonate and calcium hydroxide; (c) manufacturing solid asphalt dough by mixing the non-modified asphalt with the solidifier; (d) forming asphalt particles by hardening and pulverizing the solid asphalt dough; and (c) plating the calcium hydroxide to the solid asphalt particles. The non-modified asphalt comprises: 78-82wt% of asphalt; 8-20wt% of SF as a binder additive; 3-7wt% of crumb rubber modifier(CRM); and 0.3-0.6wt% of paraffin wax. [Reference numerals] (S10) Non-modified asphalt manufacturing step; (S20) Solidifier preparing step; (S30) Mixing step; (S40) Pulverizing step; (S50) Slaked lime coating step

Description

Solid Asphalt and Manufacturing Method of Asphalt Concrete using the same}

The present invention relates to a method for producing a solid asphalt and an asphalt concrete using the same, and more particularly, to a method for producing a modified or unmodified solid asphalt for producing a liquid asphalt as a solid, and a method for producing an asphalt concrete using the same.

In general, asphalt refers to a black or dark brown semi-solid cross-linked substance that remains after the hard portion is naturally or artificially vaporized by constituting petroleum and has a characteristic of gradually changing to a liquid phase when heated. The asphalt is used as a bonding material or an adhesive material because it is excellent in adhesion and adhesion to mineral materials, and is also used as a waterproofing material because it is insoluble in water and is not water-soluble. In addition, since the viscosity can be changed according to the purpose of use, the workability is also excellent. Due to these advantages and characteristics, asphalt has a wide range of applications, and is used for various purposes such as road pavement, dam construction, repair, waterproofing, general industrial use, and agricultural use.

When the asphalt is used for road paving, it is rare to use only asphalt itself, and it is used as an asphalt concrete (ascon) made by mixing the aggregate and the filling material in an appropriate ratio. However, pavement surfaces, such as roads and parking lots, are damaged by cracks due to traffic, temperature cycles and other environmental factors after a certain time. There is a problem in that water flows into the cracks, causing further damage.

Korean Patent Laid-Open Publication No. 2003-0080227 is known as a prior patent for improving such a problem.

Korean Patent Laid-Open Publication No. 2003-0080227 relates to a method of reinforcing and waterproofing a pavement surface, and a liquefied asphalt layer is applied on the pavement surface. The reinforcing mats are nonwoven mats having a melting point above 320 ^° F (160 ° C.) and made from fibers selected from mineral fiber polymeric fibers such as glass fibers or mixtures thereof. Liquefied asphalt is disclosed for a method of reinforcing and waterproofing a pavement surface in which water is permeated and absorbed into a reinforcing mat to form a waterproof film, and a layer of pavement material is applied on the reinforcing mat.

However, according to the preceding patent, the reinforcing mat is heated to a high temperature of 160 ° C. or higher to maintain a liquid state in which the water is dissolved, so that the plant is supplied along the pipeline or mixed with aggregate. For this purpose, there is a problem that a considerable amount of electricity is continuously consumed in the plant in order to store asphalt in a tank in a heated state throughout the year.

Republic of Korea Patent Publication No. 2003-0080227 (2003.10.11 published)

The present invention has been made to solve the problems of the prior art, it is an object of the present invention to provide a solid asphalt manufacturing method and asphalt concrete manufacturing method using the same that can reduce the cost by simplifying the plant facilities.

Another object of the present invention is to provide an environment-friendly solid asphalt production method and asphalt concrete production method using the same by reducing the generation of carbon dioxide.

Still another object of the present invention is to provide a method for producing solid asphalt using a filler as a solidifying agent and an asphalt concrete manufacturing method using the same so as to prevent the fly to dust.

Still another object of the present invention is to provide a method for producing a solid asphalt and an asphalt concrete manufacturing method using the same, which can improve the performance of a repair pavement.

In the method for producing unmodified solid asphalt according to the present invention in order to achieve the above object, (a) adding a binder additive to the asphalt to prepare the unmodified asphalt, (b) mixing limestone powder and slaked lime to prepare a solidifying agent (C) mixing the solidifying agent prepared in step (b) with the unmodified asphalt prepared in step (a) to produce a solid asphalt dough, (d) prepared in step (c) Hardening and pulverizing the solid asphalt dough to form asphalt particles, and (e) applying slaked lime to the solid asphalt particles pulverized in the step (d), wherein the unmodified asphalt in step (a) is asphalt 78 to 82% by weight, sulfur binder (SF) 8 to 20% by weight, waste tire rubber powder (CRM) 3 to 7% by weight, paraffin wax (PW) is characterized by consisting of 0.3 to 0.7% by weight.

In addition, in the method for producing unmodified solid asphalt according to the present invention, in the step (a), the unmodified asphalt is heated to a temperature of 160 to 180 ° C., and then stirred for 20 to 60 minutes by adding the binder additive. It features.

In the modified solid asphalt production method according to the present invention, (a) adding a binder additive to the asphalt to prepare the modified asphalt, (b) mixing limestone powder and calcined lime to prepare a solidifying agent, (c) mixing the solidifying agent prepared in step (b) with the modified asphalt prepared in step (a) to produce a solid asphalt dough, (d) solidifying and grinding the solid asphalt dough prepared in step (c) Forming solid asphalt particles, and (e) applying slaked lime to the solid asphalt particles pulverized in step (d), wherein the modified asphalt in step (a) is 73 to 78 wt% asphalt, binder additives Furnace sulfur (SF) is characterized by consisting of 8 to 20% by weight, waste tire rubber powder (CRM) 8 to 12% by weight, polymer 2 to 6% by weight and paraffin wax (PW) 0.3 to 0.7% by weight.

In the modified solid asphalt production method according to the present invention, in the step (a), the modified asphalt is heated to 170 ~ 190 ℃ temperature asphalt, characterized in that for 20 to 60 minutes by adding the binder additives. do.

In addition, in the method for producing unmodified or modified solid asphalt according to the present invention, the solid asphalt paste of step (c) is characterized in that the unmodified or modified asphalt and the solidifying agent are mixed in a weight ratio of 50:50 to 70:30. .

In addition, in the unmodified or modified solid asphalt production method according to the present invention, the grinding in the step (d) is characterized in that the solid asphalt dough of the step (c) is formed to a particle size of 5 ~ 10mm.

In addition, in the method for producing asphalt concrete using unmodified or modified solid asphalt according to the present invention, (a) heating and providing aggregate, (b) prepared by the method for producing unmodified solid asphalt of claim 1 Preparing the modified solid asphalt prepared by the method of preparing the modified solid asphalt or the modified solid asphalt of claim 3, (c) the aggregate prepared in the step (a) and the unmodified or modified solid prepared in the step (b) Mixing and rubbing the asphalt, the aggregate in the step (a) is characterized in that to prepare at 170 ~ 190 ℃ temperature.

In addition, in the method for producing asphalt concrete using unmodified or modified solid asphalt according to the present invention, the mixing in the step (c) is characterized in that the weight ratio of 928.6: 71.4 ~ 900: 100.

As described above, according to the solid asphalt production method and the asphalt concrete production method using the same according to the present invention, it is possible to move a mobile mixing plant and to eliminate the need for asphalt cattle and oil feeding equipment can simplify the plant facilities and reduce costs.

In addition, according to the solid asphalt production method and the asphalt concrete production method using the same according to the present invention, the power consumption is reduced due to the simplification of the plant facility can reduce the carbon dioxide is environmentally friendly.

In addition, according to the solid asphalt production method and the asphalt concrete production method using the same according to the present invention, since the solid binder is contained in the solid binder, it is possible to prevent dust flying to the dust is economical.

In addition, according to the solid asphalt production method and the asphalt concrete production method using the same according to the present invention, since the heating mixture can be used in the field as a repair asphalt, it is possible to improve the performance of the repair pavement.

1 is a process chart for explaining a method for producing unmodified solid asphalt according to the present invention;
2 is a process chart for explaining a method for producing a modified solid asphalt according to the present invention;
3 is a process chart for explaining a method for manufacturing asphalt concrete according to the present invention;
Figure 4 is a diagram showing the composition of the asphalt applied to the present invention,
5 is a graph showing the composite particle size of the aggregate,
6 is a view showing the crushed unmodified solid asphalt,
7 is a view showing a change in porosity and deformation strength according to the aggregate temperature,
8 is a view showing the specimen set for the deformation strength test,
9 is an indirect tensile strength test load schematic,
10 is a view showing a load-displacement curve,
11 is a diagram showing a repeated driving test.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings, but the present invention is not limited to the illustrated embodiments.

These and other objects and novel features of the present invention will become more apparent from the description of the present specification and the accompanying drawings.

First, the composition components of the solid asphalt applied to the present invention will be described.

As the solidifying agent, limestone powder (LP) and hydrated lime (HL) were used as ingredients for improving moldability at room temperature (FIG. 4). Asphalt concrete (ascon) is generally used as a filler (filler) with aggregate, but in the present invention, half of the filler (filler) was replaced by slaked. Since slaked lime is used as an anti-peeling agent for aggregates, it has an effect of reducing peeling damage of ascon in many hydrophilic aggregates such as granite. In addition, it is buried on the surface to prevent the adhesion between the solid asphalt (Solid asphalt (SAP)) particles and the price is cheaper than the limestone powder, its use is very profitable.

In the manufacture of unmodified solid asphalt (USA), waste rubber rubber (CRM) and sulfur (SF) of particles passed through sieve 30 were used to increase the viscosity of the binder to improve solidity. . A small amount of paraffin wax (PW) was used to lower the melting point of the binder when mixing with aggregate, which also helps to improve the solid formability at room temperature as well as to see the effect of lowering the elevated melting temperature due to CRM.

Sulfur helps to improve solid form when cooled, but it also has the effect of quantitatively replacing asphalt. Sulfur-extended asphalt is an asphalt that is increased by adding a large amount of sulfur to asphalt because sulfur is very inexpensive, and as such, it is possible to reduce the amount of asphalt used in the high oil price period, thereby contributing to economic efficiency.

In addition, in the production of modified asphalt, MSA, higher CRM content and low-density polyethylene (LDPE) with low melting point as polymers were added to improve the performance grade (PG) to 76 or more. . As shown in FIG. 4, LDPE is a polymer having almost a melting point of about 110 ° C. as a powder almost passing through the 50 sieve and almost remaining in the 30 sieve.

Aggregate is used to produce ascone coarse aggregates granite (Granite), fine aggregates used granite screenings (Screenings), fillers or solidifying agents (limestone powder and slaked lime). Table 1 shows the physical properties and particle size of the new granite aggregate used. The maximum size of the coarse aggregate was 13mm, and the fine aggregate was the aggregate of No. 8 or less. 5 is a synthetic particle size graph of the aggregate.

Characteristics of Aggregate Classification
Specificationlimit
Granite 13mm aggregate Fine aggregate Filler Heavy weight > 2.45 2.849 2.669 2.75 Absorption rate  <3.0% 0.728 1.225 - Wear rate  <35% 19.7 - -

Hereinafter, a manufacturing method of the present invention will be described with reference to the drawings.

Example 1. Unmodified  Solid asphalt manufacturing

1 is a process chart for explaining a method for producing unmodified solid asphalt according to the present invention.

As shown in Figure 1, first to prepare the unmodified asphalt (S10).

Asphalt (product number: AP-5, penetration: grade 60-80 (PG64-22), manufacturer: SK Innovation) 75 to 85% by weight, preferably 80% by weight 160 to 180 ℃, preferably 170 ℃ After heating with a binder additive, 0.3 to 0.7 wt% of paraffin wax (PW), 3 to 7 wt% of waste tire rubber powder (CRM), preferably 5 wt% and 8 to 20 wt% of sulfur (SF) Whisk 2 to 5 minutes by hand, and agitate for 20 to 60 minutes, preferably 30 minutes or more using a homogenizer to prepare unmodified asphalt.

After that, a solidifying agent is prepared (S20).

It is preferable to include 50 parts by weight of limestone powder and 50 parts by weight of limestone with respect to 100 parts by weight of the solidifying agent to prevent peeling of the aggregate and to solidify well. It is not preferable to include less than 50 parts by weight of slaked lime, the effect of preventing the peeling of the asphalt is insignificant, and if it exceeds 50 parts by weight, it is easy to cause an increase in the asphalt content.

Next, the solidifying agent is mixed with the unmodified asphalt to prepare an unmodified solid asphalt dough (S30).

The unmodified asphalt prepared in step S10 (Binder: B) and the solidifying agent (Solidifier: S) prepared in step S20 are mixed at a weight ratio of 50:50 to 70:30. This is because the amount of solid asphalt (SAP) changes according to the B: S ratio, but if the ratio is low, the amount of required unmodified solid asphalt (SAP) increases, so it is better to manufacture so that the amount of SAP decreases as much as possible. . However, increasing the ratio of B decreases the amount of S, so it is difficult to solidify. Conversely, if the ratio of B is low, there is a contradiction that it is easy to solidify.

Thereafter, the SAP dough is hardened and ground (S40).

SAP dough prepared in step S30 is poured into a wide pan 4 ~ 8mm thick to cool quickly and stored in the freezer to cool. A freezer may be used to shorten the cooling time. The mixture is pulverized to a size of 5 to 10 m at room temperature as shown in FIG. 6 by one of a conical grinding mill, a roll mill or a ball mill to increase the surface area and facilitate thermal mixing so as to facilitate mixing. If it exceeds 10mm, it is preferable to grind to a particle size of 10mm or less because the SAP does not melt quickly upon contact with the heated aggregate, that is, it does not melt.

Next, slaked lime is applied to the crushed SAP (S50).

Put the crushed SAP particles in the step S40 into a hydrated lime bucket at room temperature so that the hydrated lime is sufficiently buried on the surface and stored.

Upon completion of the step of laminating calcified SAP as described above, an unmodified solid asphalt is obtained.

Example 2. Modified Solid Asphalt Preparation

2 is a process chart for explaining a method for producing a modified solid asphalt according to the present invention.

As shown in Figure 2, first to produce a modified asphalt (S10).

Asphalt (product number: AP-5, penetration grade: 60-80 (PG 64-22), manufacturer: SK Innovation) was heated to a temperature of 170 ~ 190 ℃, preferably 180 ℃, by adding a binder additive The modified asphalt is prepared by stirring using a homogenizer for 20 to 60 minutes, preferably 30 minutes.

The modified asphalt is 73 to 78% by weight asphalt, 8 to 12% by weight rubber tire (CRM), 8 to 20% by weight sulfur (SF), 2 to 6% by weight polymer, and 0.3 to 0.7 paraffin wax (WAX) It is composed of 7% by weight, preferably 75.5% by weight asphalt, 10% by weight waste tire rubber powder (CRM), 10% by weight modified sulfur (MS), 4% by weight polymer and 0.5% by weight paraffin wax (PW).

After that, a solidifying agent is prepared (S20).

It is preferred to include 50 parts by weight of limestone powder and 50 parts by weight of limestone with respect to 100 parts by weight of the solidifying agent to prevent peeling of the aggregate and to prevent adhesion between asphalt particles by being buried on the surface. It is not preferable to include less than 50 parts by weight of slaked lime, the effect of reducing the peeling damage of the modified asphalt, and to include more than 50 parts by weight, it is not easy to solidify.

Next, the solidifying agent is mixed with the modified asphalt to prepare a modified solid asphalt dough (S30).

The modified asphalt (Binder: B) prepared in step S10 and the solidifying agent (Solidifier: S) prepared in step S20 are mixed at a weight ratio of 50:50 to 70:30. This is because the amount of modified solid asphalt (SAP) changes according to the B: S ratio, but if the ratio is low, the amount of required modified solid asphalt (SAP) increases, so it is better to manufacture so that the amount of SAP is increased by increasing the ratio of B as possible. . However, increasing the ratio of B decreases the amount of S, so it is difficult to solidify. Conversely, if the ratio of B is low, there is a contradiction that it is easy to solidify.

Thereafter, the modified solid asphalt dough is hardened and pulverized (S40).

Asphalt dough prepared in step S30 is poured into a wide pan 4 ~ 8mm thick to cool quickly and stored in the freezer to cool. If the dough stored in the freezer becomes solid and becomes brittle, take it out and break it quickly. To increase the SAP surface area and thermal conductivity to facilitate the mixing, it is pulverized to a size of 5 to 10 mm at room temperature by one of conical mills, roll mills, or ball mills. If it exceeds 10 mm, the SAP does not melt quickly upon contact with the heated aggregate, that is, it does not melt, so it is preferable to grind to a particle size of 10 mm.

Next, hydrated lime is buried in the ground SAP (S50).

Put the SAP particles crushed in step S40 into a hydrated lime bucket at room temperature so that the hydrated lime is sufficiently buried on the surface, and then stored.

Upon completion of the step of applying the lime to the pulverized SAP as described above, a modified solid asphalt is obtained.

Example 3 Asphalt Concrete

3 is a process chart for explaining a method for producing asphalt concrete according to the present invention.

As shown in Figure 3, first, aggregate is prepared by heating (S10).

The aggregate is heated to a temperature of 170 to 190 ° C, preferably 175 to 185 ° C. When using the unmodified solid asphalt in the mixing and rubbing step to be described later, the temperature of the aggregate is heated to 170 ~ 190 ℃, preferably 175 ℃ degree, when using the modified solid asphalt, 170 ~ 190 ℃, Preferably heating to a temperature of 185 ℃.

Coarse aggregate, fine aggregate, filler (filler) is used as the aggregate. The coarse aggregate uses granite crushed stone (granite), and the fine aggregate uses granite screenings (screenings).

Next, prepare an unmodified or modified solid asphalt (S20).

Prepare the unmodified or modified solid asphalt prepared by the method of Example 1, Example 2 above.

Thereafter, the aggregate is mixed with unmodified or modified solid asphalt (SAP) and rubbed (S30).

The aggregate prepared in step S10 and the SAP prepared in step S20 are mixed and mixed at a predetermined ratio. It is preferable to adjust the said constant ratio to 928.6: 71.4-900: 100. When SAP is blended at a weight ratio of 70 or less, additional limestone filler may be required.If the weight ratio of SAP is more than 100, the amount of solid asphalt is relatively high, and the mixture cools quickly, resulting in poor workability. In addition, because the temperature of the aggregate must be heated higher, it is disadvantageous because it is uneconomical and has a large amount to handle.

When the mixing and rubbing step as described above is completed, asphalt concrete (S40) is obtained.

Experimental Example 1. Asphalt Concrete Manufacturing

In the production of asphalt concrete using the unmodified solid asphalt and modified solid asphalt prepared in the above embodiment, an experiment was performed as follows to determine an optimal asphalt concrete composition ratio.

First, R & D was carried out to select a B: S ratio having a high solids, good shelf life, high content of modified or unmodified asphalt, and then adjusting a binder content to obtain a predetermined PG grade. As shown in Tables 2 and 3, the lowest 56 to 58, 60, 64 was sequentially performed.

Unmodified Solid Asphalt (USA) Formulation Table for Material Selection division ratio Unmodified asphalt (g) Solidifying agent (g) system
(g) Remarks Asp
(80%) CRM
(5%) Wax
(0.5%) Polymer
(0%) MS
(10%) sub Total Limestone Powder Lime lime AP-5 100: 0 1,000 0 0 0 0 1,000 0 0 1,000 control
USA

56:44 473.20 28.0 2.80 0 56.0 560 220 220 1,000
Unmodified

58:42 490.10 29.0 2.90 0 58.0 580 210 210 1,000 60:40 507.00 30.0 3.00 0 60.0 600 200 200 1,000 62:38 523.90 31.0 3.10 0 62.0 620 190 190 1,000

Formulation Table for Material Selection for Modified Solid Asphalt (MSA)
division
ratio Modified asphalt (g) Solidifying agent (g)
(G)
Remarks Asp
(75.5%) CRM
(10%) Wax
(0.5%) Polymer
(4%) MS
(10%) sub Total
(100%) Limestone Powder Lime lime AP-5 100: 0 1,000 0 0 0 0 1,000 0 0 1,000 control
MSA

56:44 422.80 56.0 2.80 22.4 56 560 220 220 1,000
Reforming
58:42 437.90 58.0 2.90 23.2 58 580 210 210 1,000 60:40 453.00 60.0 3.00 24.0 60 600 200 200 1,000 62:38 468.10 62.0 3.10 24.8 62 620 190 190 1,000

According to the B: S ratio in the modified solid asphalt, the amount of modified solid asphalt used in the production of asphalt concrete is determined. For example, as shown in Table 4, 1.0 ton (1,000 kg) of ordinary asphalt concrete for the surface layer having an optimum asphalt content of 5.0%, the amount of material used is 50 kg of modified asphalt, aggregate (coarse aggregate, fine aggregate, 950 kg). If you use modified solid asphalt (MSA) with a B: S ratio of 6: 4 to make this asphalt concrete, you will need to add 83.3 kg MSA and 916.7 kg aggregate. 50 kg, which accounts for 60% in MSA 83.3 kg, is the binder and the remaining 33.3 kg is used as a filler.

The amount of solid asphalt (SAP) required to produce one ton of asphalt concrete with an optimum asphalt content of 5.0%
OAC (%)
B: S ratio Weight (kg) MSA ratio by agg. wt. (%) MSA Aggregate
Total
Binder Filler Total
5.0%

50:50 50.0 50.0 100.0 900.0 1,000 10.0% 60:40 50.0 33.3 83.3 916.7 1,000 9.09% 70:30 50.0 21.4 71.4 928.6 1,000 7.69% 75:25 50.0 16.7 66.7 933.3 1,000 6.67%

If you use MSA with B: S = 5:50, you will add 100kg MSA and 900kg aggregate. In this case, 50 kg, which accounts for 50% in the MSA, is used as a binder and the remaining 50 kg is used as a filler. In these two cases, the percentage of binder (B) in the MSA differs by 10 percentage points. In other words, the requirement of 60:40 MSA is 83.33kg, whereas the 50:50 MSA is increased by 20% to 100kg.

In addition, the latter must melt 100 kg of modified solid asphalt (MSA) (11.11% by weight of aggregate) with 900 kg of heated aggregate, and the former melts 83.33 kg MSA (9.09% by weight of aggregate) with 916.67 kg of aggregate. This will be. In the plant, the MSA is put at room temperature, so if the amount of MSA is higher than the amount of aggregate, the heated aggregate will cool down quickly, resulting in poor workability. It is therefore advisable to make the binder content as high as possible in the MSA.

In addition to the disadvantage of increasing the amount of unmodified solid asphalt or modified solid asphalt in addition to the disadvantage of increasing the handling amount, the ratio is larger than the amount of aggregate, so the problem of heating the aggregate higher to ensure workability is very important.

Therefore, in order to prepare solid asphalt (SAP) particles (grains) having the maximum binder content that can be handled at room temperature, the appropriate addition range for each material was selected through preliminary tests.

As a result, as shown in Tables 5 and 6, USA or MSA confirmed that when the B: S ratio is 60:40, it can be mixed with aggregate to produce an optimal asphalt concrete.

Proper mixing ratio for manufacturing 1,000 g of solid asphalt by type division ratio Modified Asphalt B (g) Solidifying Agent S (g) system
(g) Remarks Asp CRM PW Polymer MS sub Total LP HL AP-5 100: 0 1,000 0 0 0 0 1,000 0 0 1,000 control USA 60:40 507 30 3 0 60 600 200 200 1,000 Unmodified MSA 60:40 453 60 3 24 60 600 200 200 1,000 Modification

Content (%) Range by Various Binder Materials division
Modified, Unmodified Asphalt (%) asphalt CRM PW Polymer MS system Unmodified (USA) 84.5 ± 6.2 5 ± 1 0.5 ± 0.2 0 10 ± 5 100 Reform (MSA) 75.5 ± 8.2 10 ± 2 0.5 ± 0.2 4 ± 1 10 ± 5 100

Experimental Example 2. Binder Test

In order to measure the performance grade (PG) and kinematic viscosity (cp) at 135 ℃ of the modified solid asphalt, unmodified solid asphalt, asphalt cement prepared in the above-described experiment was carried out as follows.

A high shear test to determine the performance grade (PG) was performed by a dynamic shear rheometer (DSR) and a bending beam rheometer (BBR) by a low temperature test.

The DSR analyzed the viscosity and elastic behavior of the asphalt binder by measuring the complex shear modulus (G ^* ) and phase angle (δ) of the binder, and after analysis, the obtained G * / sin δ PG high temperature grade was determined.

The BBR was subjected to long-term aging of the binder to apply the creep load in bending mode to the asphalt beam specimen at a constant low temperature, ie very low pavement temperature, and to determine the PG low temperature grade from the obtained stiffness and m-value. .

As a result, as shown in Table 7, the unmodified asphalt USA was measured in the 64-22 grade, such as AP-5, and the performance grade (PG) of the modified asphalt MSA was 76-22. Therefore, it was found that the unmodified asphalt USA, which is a general solid asphalt, is a 64-22 grade like ordinary asphalt. The modified solid asphalt MSA showed grades 76-22, and it was confirmed that it satisfies the binder performance grade generally required for modified asphalt.

Asphalt performance grade and kinematic viscosity Binder AP-5 No reformation (USA) Reform (MSA) PG rating 64-22 64-22 76-22 Kinematic Viscosity at 135 ° C (cp)
(Kinematic viscosity at 135 ℃) 472 567 1,875

Experimental Example 3. Formulation Design and Ascon Production

For the comparative evaluation, two types of binders were used, each of which was used as a liquid by heating the same kind of binder as the solid asphalt at room temperature for each solid asphalt (SAP). In the case of a solid, since the binder is introduced at room temperature, the aggregate temperature is heated to 10 ° C. higher than when mixed with the liquid asphalt to maintain the temperature when mixed with the aggregate.

Therefore, in the case of solid USA (unmodified), the aggregate temperature was used at 175 ° C and the binder at room temperature (25 ° C), and the mixture was compacted after short-term aging for 1 hour at 160 ° C. The required specimen was prepared. When using the liquid asphalt and the temperature was compared as shown in Table 8.

Aggregate and Binder Temperature by Binder Type Binder Binder Temperature (℃) Aggregate Temperature (℃) Short aging temperature (℃) Remarks designation condition AP-5 Liquid 160 165 160 control USA (unmodified) Liquid 160 165 160 Unmodified
solid 25 175 160 MSA (Modified) Liquid 170 175 165 Reforming
solid 25 185 165

In order to determine the optimum asphalt content of the mixture in the present invention, the Ministry of Land, Transport and Maritime Affairs guidelines were applied. Compaction was carried out using a superpave gyratory compactor (SGG) and the strain strength (S _D ), void in mineral aggregate (VMA), voids filled with Asphalt (VFA) were used as OAC criteria. It was. The OAC determinants for the pavement of general roads are based on porosity of 3-5%, VFA 65-80%, strain strength (S _D ) of 3.2 MPa (4.25 MPa for modified asphalt) and 13 mm aggregate clearance (VMA). It was made into% or more. Among the asphalt contents satisfying all these criteria, the asphalt content at which a porosity of 4% was obtained was determined as OAC. In the design, the asphalt content was changed to 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, and 7.0% in six stages, and the basic mixture and the modified mixture were compacted 100 times with a turning compactor.

Using a granite aggregate with a maximum dimension of 13 mm, two solid asphalts, in addition to the asphalt AP-5, were divided into solid and liquid binders. In the case of a solid pallet, since the temperature of the binder is room temperature, it is necessary to increase the aggregate temperature because the temperature difference slightly affects workability when rubbed.

As a result, when the unmodified USA is used, when the aggregate temperature is increased by about 10 ° C on average, a mixture temperature similar to that of using asphalt (AP-5) at 165 ° C can be obtained. Therefore, the optimum aggregate temperature of the unmodified (USA) mixture was determined to be 175 ° C, 10 ° C higher than asphalt.

In the case of modified asphalt, the temperature is very important, and the porosity and strain strength were compared according to the aggregate temperature in order to select the optimum aggregate temperature with 6% of the asphalt content. As a result, as shown in Table 9, as the aggregate temperature is increased by 5 ° C, the porosity is lowered and the deformation strength is increased. As shown in FIG. 7, the temperature satisfying the reference porosity 4% is about 183 ° C. At this temperature, the strain strength satisfies S _D ≥4.25 MPa, the VOD and Void filled with asphalt (VFA). Therefore, it was adjusted slightly upward so that the compaction could be stably determined, and 185 ° C was determined as the optimum aggregate temperature.

Porosity and Strain Strength According to Aggregate Temperature Binder Agg. temp.
(℃) Air void
(%) VMA
(%) VFA
(%) S _D
(MPa) MSA
(Modification) 175 4.27 18.25 76.63 4.6 180 4.20 18.26 76.61 4.7 185 3.74 17.82 79.02 4.9

Temperature Treatment and Optimum Asphalt Content (OAC)
Binder type designation Aggregate Temperature
(℃) Binder temperature
(℃) Short-term aging OAC Remarks Temperature
(℃) time
(Hr)
Unmodified Liquid AP5 165 165 160 One 5.6% Base asphalt Pre-melted USA 165 165 160 One 5.7% Solid USA 175 25 160 One 5.8%
Reforming Liquid PMA 175 175 165 One 5.8% Pre-melted MSA 175 175 165 One 5.9% Solid MSA 185 25 165 One 5.9%

In the mixing design, in Table 10, the liquid asphalt is a liquid asphalt, and the liquid PMA is a liquid-modified asphalt containing only a modification additive without limestone and lime, which are solids, when the MSA is manufactured. . Pre-melted USA and MSA are solid asphalts melted at the binder temperatures shown in Table 10, so they are liquid but contain slaked lime and limestone, resulting in liquid asphalt (AP-5) or liquid PMA. It is different from, and is to compare the difference between using the solid binder and the solid state at room temperature.

As a result, the OAC of the unmodified solid asphalt (USA) is 5.9%, which is 0.2% higher than that of 5.6% of the pure binder-based asphalt, indicating that the asphalt takes more time. However, it did not show any difference from the case of pre-melted melting. This is because the solid agent added for solidification lowered the fluidity of the binder and thus slightly increased the OAC, but there was a difference from using it beforehand.

The OAC of Liquid PMA, a modified asphalt, was 0.2 percentage points higher than that of unmodified ordinary asphalt (AP-5). This can be seen due to the difference in the fundamental viscosity of the modified asphalt and the normal asphalt, as shown in Table 10. Pre-melted or solid MSA's OAC was not higher than liquid PMA between the same modified asphalt, so it was found that there was little difference between solid asphalt or pre-melted in modified asphalt. .

Experimental Example 4. Strain Strength

Deformation strength is a patent No. 10-0792830 (holder for deformation strength of asphalt concrete and measuring method of deformation strength using it: registered on Jan. 02, 2008). Included in It is also a feature value published in the American ASTM Journal (Kim et al. 2011) and the European Journal (Kim et al. 2004, Doh et al. 2007) that is recognized as an estimate of plastic deformation resistance. Deformation strength is measured by Kim Test, and under the loading of load rod (40mm in diameter, 10mm in circular cutting radius), the mixture is deformed by compression shearing and destroyed, similar to plastic deformation. FIG. 8 shows a photograph immediately before applying a load at a rate of 30 min / min to a 100 mm diameter specimen immersed in a 60 ° C. constant temperature water bath for 30 minutes. Deformation strength was calculated by the following equation (1) to obtain the maximum load (P) and the deformation value (y) at the time when the load rod is increased by y from the specimen surface.

In the above equation, S _D = strain strength (MPa), P = ultimate load (N), and y = vertical strain value (mm).

Since many studies have confirmed that the deformation strength of asphalt mixtures has a high correlation with the plastic deformation resistance, the high deformation strength means that it is also resistant to plastic deformation. Therefore, the asphalt mixture should have a certain level of deformation strength according to the guidelines of the Ministry of Land, Transport and Maritime Affairs. Deformation strength (S _D ) was calculated using Equation 1 from P and y obtained by performing a Kim Test with an OAC specimen having a porosity of 4 ± 0.5%.

As a result, as shown in Table 11 below, the deformation strength of the mixture using the base asphalt AP-5 and the unmodified asphalt (USA) was 3.3-3.6 MPa, which passed the standard value of 3.2 MPa. In case of using modified asphalt (PMA), all of them passed the minimum reference value of 4.25 MPa, above 4.7 MPa. In addition, there is little difference in strain strength between solid and liquid phases, and the porosity of the modified solid asphalt mixture is in the range of 4 ± 0.5%, but lower.

Strain Strength Components of Mixtures Prepared with Each OAC division condition bookbinder
designation OAC
(%) Air void
(%) VMA
(%) VFA
(%) S _{D
( MPa )} S _D Reference _{( MPa )}
Unmodified Liquid AP5 5.6 4.09 14.68 72.12 3.6
3.2 and up Pre-melted USA 5.7 3.87 17.85 78.30 3.4 Solid USA 5.8 3.93 17.95 78.13 3.5
Reforming Liquid PMA 5.8 4.10 17.87 77.91 4.8
4.25 or later Pre-melted MSA 5.9 4.21 18.28 76.98 4.7 Solid MSA 5.9 3.74 17.82 79.02 4.7

Experimental Example 5 Indirect tensile strength

Asphalt tensile strength (S _t ) is measured by Indirect Tensile Strength (ITS) test. The load generates a relatively uniform tensile stress along the diameter plane and eventually splits along the vertical diameter plane, which leads to fracture and thus serves as an indicator of crack resistance of the package.

FIG. 9 is a schematic diagram of a specimen mounted to perform an indirect tensile strength test, and FIG. 10 is a diagram showing a load-displacement curve obtained from an ITS test.

As shown in Figure 9 with the optimum asphalt content obtained through the blend design, a specimen 100 mm in diameter was produced and placed in a thermostat at 25 ° C. for 48 hours. A graph as shown was obtained. At this time, as shown in Figure 9, the load was used a loading device having a load band of 12.5 ~ 12.7mm width having the same curvature as the specimen above and below the specimen.

Tensile strength (St) is calculated as shown in Equation 2 below.

In Equation 2, S _t = tensile strength of asphalt concrete, P = ultimate load (N), t = specimen thickness (mm), D = specimen diameter (mm).

Table 12 shows the average values of three indirect tensile strengths calculated by [Equation 2] using the maximum load (P) measured on the specimens prepared for each binder type and the thickness and diameter of the specimens. First, the asphalt (AP5) showed an indirect tensile strength value of 0.84 MPa. USA, the unmodified asphalt, showed a slightly higher average of 0.9 MPa than asphalt (AP-5), but there was no significant difference. Although not specified, indirect tensile strengths of 1.0 MPa are generally considered to be quite good mixtures. In the case of using modified asphalt, PMA or MSA, the overall effect was about 20% higher than that of asphalt (AP-5).

Tensile strength measured on specimens prepared for different asphalt types Binder Designation OAC Air gap ratio
(Air Void) VMA Volatile fatty acids
(VFA) ITS
_(MPa)
Unmodified Liquid AP-5 5.6% 4.14 17.31 76.06 0.84 Pre-melted USA 5.7% 3.95 17.92 77.95 0.91 Solid USA 5.8% 3.95 17.97 78.04 0.88
Reforming Liquid PMA 5.8% 4.07 18.11 77.39 1.21 Pre-melted MSA 5.9% 4.17 18.25 77.13 1.15 Solid MSA 5.9% 3.88 17.94 78.39 1.20

Experimental Example 6. Repeated driving test

As a result of the experiment of the two characteristics there is no difference between the case of pre-dissolution and solid, in this experiment, only two types of liquid and solid were compared. The mixture was mixed with the optimum asphalt content (OAC) determined from the mixing design, and a slab specimen having a size of 305 mm × 305 mm × 50 mm having a target porosity of 4 ± 1% was produced by a roller compactor. The produced slab was cooled at room temperature for 12 hours, demolded in a mold, cut in two parts by measuring physical properties, and cured in a thermostat at 25 ° C.

The prepared mixture is WT test in 3 days (72 hours), so it is cured for 48 hours after being cut in half. Then, the specimen was placed in a WT chamber at 60 ° C. for 6 hours or more, and the test body was completely heated to 60 ° C. at the test temperature for 72 hours. The WT tester traveled 2,520 times for 60 minutes at a speed of 42 pass / min under the axial load causing 686 N of ground pressure to measure the cumulative depth of settlement along the number of passages. The material of the wheel is steel, diameter 200mm, width 50mm, and the reciprocating distance is 200mm. As illustrated in FIG. 11, in order to prevent aggregate breakage and asphalt adhesion due to direct contact between steel materials and specimens, a polypropylene nonwoven fabric was covered on the surface to roll the cast iron wheel thereon.

This study was performed following the test method of dynamic stability (KS F2374, 2000) of the Korean Industrial Standard (KS). Dynamic stability was calculated through Equation 3.

In Equation 3, DS = dynamic stability (times / mm), t ₁ = 45 minutes, t ₂ = 60 minutes, d ₁ = deformation amount at t ₁ (sedimentation depth (mm)), d ₂ = deformation amount at t ₂ (sedimentation depth (mm)), C = correction factor when using a crank driven tester Indicates = 1.

The cyclic test is the most common test for evaluating plastic deformation resistance. In this study, a slab with 3-5% target porosity was fabricated with OAC content. One slab prepared was divided into one half to perform two tests and the average value was used for analysis. Repeated run tests yielded final settlement depths and dynamic stability.

The results showed a final settlement depth of 5.47 mm for the base asphalt (AP-5) and a dynamic stability (DS) of 1068 over 1,000. In unmodified USA, dynamic stability (DS) and final settlement depth were found to be very similar to AP-5. On the other hand, in case of modified asphalt, PMA and MSA, the final settlement depth was about 3.0mm and the dynamic stability (DS) was also higher than 3500.

Identification stability and final settlement depth for each mixture Binder
Type
MIX Type
designation
OAC (%)
Air Void (%)
No. Plastic deformation
(Rut Depth)
(mm) Dynamic stability
(DS)
(Pass / min)

Unmodified Liquid
(Liquid)
AP5
5.6
3.91 One 5.81 1,068 2 5.12 1,054 mean 5.47 1,061 solid
(Solid)
USA
5.8
3.86 One 5.43 1,014 2 5.93 1,005 mean 5.68 1,010

Reforming Liquid
(Liquid)
PMA
5.8
4.57 One 2.96 3,316 2 2.93 3,706 mean 2.95 3,511 solid
(Solid)
MSA
5.9
4.53 One 3.09 3,031 2 3.37 3,270 mean 3.23 3,151

As mentioned above, although the invention made by the present inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example and can be variously changed in the range which does not deviate from the summary.

Claims (8)

(a) adding a binder additive to the asphalt to produce unmodified asphalt,
(b) mixing limestone powder with hydrated lime to prepare a solidifying agent,
(c) mixing the solidifying agent prepared in step (b) with the unmodified asphalt prepared in step (a) to produce a solid asphalt dough;
(d) hardening and pulverizing the solid asphalt dough prepared in step (c) to form asphalt particles, and
(e) applying slaked lime to the solid asphalt particles pulverized in the step (d);
In the step (a), the unmodified asphalt is 78 to 82% by weight asphalt, 8 to 20% by weight sulfur (SF) as a binder additive, 3 to 7% by weight of waste tire rubber powder (CRM), paraffin wax (PW) 0.3 ~ Method for producing an unmodified solid asphalt, characterized in that consisting of 0.7% by weight.
The method of claim 1,
In the step (a), the unmodified asphalt is heated to 160 ~ 180 ℃ temperature, the method of producing an unmodified solid asphalt, characterized in that the stirring for 20 to 60 minutes by adding the binder additive.
(a) adding a binder additive to the asphalt to produce modified asphalt,
(b) mixing limestone powder with hydrated lime to prepare a solidifying agent,
(c) mixing the solidifying agent prepared in step (b) with the modified asphalt prepared in step (a) to produce a solid asphalt dough;
(d) hardening and pulverizing the solid asphalt dough prepared in step (c) to form solid asphalt particles, and
(e) applying slaked lime to the solid asphalt particles pulverized in the step (d);
In the step (a), the modified asphalt is 73 to 78 wt% asphalt, 8 to 20 wt% sulfur (SF) as a binder additive, 8 to 12 wt% waste tire rubber powder (CRM), 2 to 6 wt% polymer and paraffin Wax (PW) method for producing a modified solid asphalt, characterized in that consisting of 0.3 to 0.7% by weight.
The method of claim 3,
The modified asphalt in step (a) is heated to 170 ~ 190 ℃ temperature asphalt, and then adding the binder additive for stirring the modified solid asphalt, characterized in that for 20 to 60 minutes.
The method according to claim 1 or 3,
The solid asphalt dough of step (c) is a method for producing unmodified or modified solid asphalt, characterized in that the unmodified or modified asphalt and the solidifying agent is mixed in a weight ratio of 50:50 to 70:30.
The method according to claim 1 or 3,
Grinding in the step (d) is a method for producing unmodified or modified solid asphalt, characterized in that to form the solid asphalt dough of the step (c) to a particle size of 5 ~ 10mm.
(a) heating the aggregate to provide it,
(b) preparing an unmodified solid asphalt prepared by the method of preparing the unmodified solid asphalt of claim 1 or a modified solid asphalt prepared by the method of producing the modified solid asphalt of claim 3,
(c) mixing and mixing the aggregate prepared in step (a) with the unmodified or modified solid asphalt prepared in step (b),
In step (a), the aggregate is a method for producing asphalt concrete using unmodified or modified solid asphalt, characterized in that it is provided at a temperature of 170 ~ 190 ℃.
The method of claim 7, wherein
Mixing in step (c) is 928.6: 71.4 ~ 900: 100 asphalt concrete manufacturing method using unmodified or modified solid asphalt, characterized in that the weight ratio.

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